The present invention generally relates to bodily fluid sampling devices and more specifically, but not exclusively, concerns a technique for mass-producing integrated disposables.
The acquisition and testing of bodily fluids is useful for many purposes and continues to grow in importance for use in medical diagnosis and treatment, such as for diabetes and in other diverse applications. In the medical field, it is desirable for lay operators to perform tests routinely, quickly, and reproducibly outside of a laboratory setting with rapid results and a readout of the resulting test information. Testing can be performed on various bodily fluids and, for certain applications, is particularly related to the testing of blood and/or interstitial fluid.
Recently, integrated disposables, such as lancet integrated test strips and microsamplers, have been developed in which a test strip is integrated with a lancet so as to form a single disposable unit. The term “disposable” commonly refers to components, such as test strips and lancets, that are typically used once for a test and then discarded or disposed of afterwards, which contrasts with other more permanent (and expensive) components, like meters and firing mechanisms, that are repeatedly used for multiple tests. Lancets are usually discarded after use because lancets are contaminated with blood or other biological fluids that can create a biohazard. Likewise, test strips are discarded after a single use due to blood contamination during testing. Additionally, given that the reagents used for testing are consumed during analysis, test strips by their very nature can usually perform a single accurate test. Integrated disposables typically combine the functions of a test strip with a lancet or a needle to form a single disposable unit.
While these integrated disposables have somewhat simplified the collection and testing of fluid samples, there are still a number of issues that need to be resolved before a successful commercial unit can be implemented. Considering that integrated disposables are only used once and then discarded after each test and typically multiple tests are conducted in a day, the disposables need to be inexpensive and must be able to be produced in high volumes to satisfy consumer demand. A related issue concerns sterilizing and maintaining the sterility of the lancet so as to minimize the risk of infection. In practice, conventional plastic or syringe-type caps that are used to maintain the sterility of typical lancets cannot be incorporated with integrated disposables for several reasons, especially for those designs with lancets that are moveable relative to the rest of the test strip. With typical syringe-type caps, the cap encapsulates the lancet, and the cap is removed by pulling or twisting the cap off the lancet. However, the removal of the cap from the lancet without destroying or damaging the integrated disposable is difficult or even practically impossible. Moreover, automatic cap removal with such caps can be difficult.
Integrated disposables have been proposed in which the lancet is encapsulated within a sterilized plastic body or a molded plastic plug that encloses one end of a lancet chamber. During lancing, the lancet pierces the body so as to extend from the body and lance the tissue. Such a design is suitable for automated systems because the lancet can be fired without the need to remove a protective cap. Given their bulky and rigid nature, these types of designs are not well suited for magazines, drums, cassettes, cartridges, and the like, however. The encapsulating plastic also creates a rather large profile which does not allow a plurality of integrated devices to be packed in a tight package. Moreover, the injection molding required to manufacture these types of integrated devices can make the devices considerably more expensive as well as more difficult to assemble. Such designs can also limit how small the lancet can be because the lancet has to be rigid enough to still be able to puncture the seal.
Other integrated disposable designs have been proposed in which the entire unit is sealed within a protective packet. However, these designs require the entire disposable unit to be sterilized at the same time, which results in a whole host of difficulties. Unfortunately, sterilization techniques for lancets, such as radiation, adversely affect the chemical enzymes of the test strip. Hence, if left uncompensated, the accuracy of the test strip can be significantly hampered. Moreover, certain desirable sterilization techniques for lancets are impractical when the lancet and test strip are combined together because these techniques tend to damage or even destroy components on the test strip. In addition, undesirable cross contamination can occur between the lancet and the test strip when sealed in the same protective packet. For instance, components of the test strip, such as chemicals, biological components, adhesives, and the like, can migrate within the packet onto the lancet, thereby possibly compromising the sterility of the lancet.
Thus, needs remain for further contributions in this area of technology.